A SYNOPSIS OF EUDEJEANIA—SABROSKY 147 
basally; width of the front at the vertex in the male 0.38 times the 
width of the head (average of 10 males, Bogot4; range, 0.35-0.39) ; 
female with 1 or 2 pairs of proclinate frontoorbital bristles, apparently 
typically two (cf. introductory discussion for note on variation). 
Body color to the naked eye as dark as the black species, but under 
a microscope the abdomen is dark reddish brown, sometimes with a 
trace of a narrow median black vitta; acrostichal and dorsocentral 
bristles variable in number (cf. discussion that follows). 
Wing membrane and veins brown; subepaulet (basicosta) orange- 
yellow. 
Legs entirely bright reddish yellow, the tibial and tarsal bristles and 
hairs concolorous, rarely an isolated tibial bristle black; tarsal claws 
reddish yellow with black tips; hind tibia with a row of 8-10 anterodor- 
sal bristles of varying lengths; tibial hairs short and not so dense as 
in some of the other species, the ground cvlor of the tibia readily 
apparent; dorsal (extensor) surface of the hind tibia glabrous except 
for a few yellow hairs near the base. 
Length of the body typically about 16 mm., with a few specimens as 
small as 138 mm. . 
Type.—Male, U.S.N.M. No. 58279. 
Holotype, male, and allotype, Bogota, Colombia (B. Guevara), in 
the United States National Museum. Paratypes: Conompra: 62 
males, 115 females, same data as holotype [U.S.N.M.]; female, 
Usaquén, Cundinamarca, September 30, 1939, alt. 2,700-8,000 m. 
(H. Osorno) ; male, ibid., June 9, 1939, same alt. (LL. Richter) ; male, 
ibid., June 19, 1941, alt. 2,850 m. (L. Richter) ; male, Paramo Guerrero 
(Zipaquira-Pacho), Cundinamarca, September 26, 1940, alt. 3,080 m. 
(H. Osorno) [Inst. Cien. Nat., Bogoté]. Ecuapor: male, Quito, 
2,850 m.; male, 2 females, Aloag, 2,922 m. (F. Campos R.) [U.S.N.M.]. 
The species is named in honor of the late John Merton Aldrich, for 
many years curator of insects of the United States National Museum. 
This species is superficially quite similar to ’. huascarayana Town- 
send, but the latter has a black abdomen and the front of the male is 
noticeably narrower. The legs appear more strikingly reddish yellow 
in aldrichi, but of course this is a comparative matter that is difficult 
to grasp except by direct comparison of specimens. 
The availability of the fine series of this species from one locality 
(Bogota) made it possible to study the variation in certain character- 
istics that have usually been regarded as significant. For this purpose, 
a sample of 50 specimens, 25 of each sex, was tabulated. 
It was at once apparent that these flies exhibit a considerable degree 
of variation in chaetotaxy, even in characters that have been regarded 
as of generic significance. This was particularly true in the acros- 
tichal and dorsocentral bristles. If we may judge from predominance 
